In this lesson, students count to read and write multi-digit numbers up to the ten-thousands place. They also count to develop a sense of the magnitude of 10,000. In the previous lesson, students counted by thousands and created 10 groups of 1,000 to make 10,000. This work continues to build awareness of the structure of our number system with the base of ten (MP7). In this lesson, students practice writing numbers up to 100,000, which sets the stage for 100,000 as a new unit in base-ten in the lessons that follow.

What did you see or hear that surprised you about students’ sense of multi-digit numbers? What question do you wish you had asked today that would have provided great insight into student thinking?